Video conferencing systems allow multi-dimensional communication between participants separated by physical distance. The advancement of video conferencing provides businesses and individuals a rich communication experience that combines video with audio and effectively simulates the face-to-face communication that is a lynch-pin of understanding.
Early video conferencing systems required networks dedicated to the video conference. For example, in prior systems described in U.S. Pat. Nos. 4,686,698, 4,710,917, 4,847,829, and 5,014,267 to Tompkins et al., audiovisual terminals are linked with a video-conferencing switch through a coaxial cable network. The dedication of the network and associated terminals resulted in high cost and limited flexibility, but provided quality video conferencing at an early date.
The advent of PC-based video conferencing systems has made video conferencing a more economical proposition. For example, U.S. Pat. No. 5,506,954 to Arshi et al. discloses a relatively low-cost PC-based video conferencing system. Low cost has, in the past, however, usually meant limited switching sophistication that limits the conference to two participants. If more than two parties wish to participate, a video switching system is required. Video conferencing switching systems have generally included a "multi-point" control unit (MCU) which, typically, includes multiple communication ports that can be selectively interconnected to provide appropriate connection among participant terminals or devices.
Typical switching systems have required conferences to be scheduled in advance. Generally, a fairly complex and indirect methodology must be followed that typically implicates a reservation system or operator that controls the MCU to initiate and direct the video conference according to a prearranged schedule. Conference set-up complexity, both in terms of operator involvement and conference command structure have delayed the inevitable ubiquity of video conferencing.
On-demand conferencing based on user control from a touch-tone (DTMF) keypad is described in Bellcore Generic Requirements GR-1337-CORE. The method described in GR-1337 requires, however, a complex command structure and set-up times which are generally lengthy. Audio conferencing based on the GR-1337-CORE model has benefitted from recent innovations such as that described in U.S. Pat. No. 4,653,090 in which a graphical user interface is purportedly provided to simplify call set-up. On-going graphical control of a video conference is not, however, provided.
Other systems such as that disclosed in U.S. Pat. No. 5,555,017 to Landante et al. have provided an MCU that purportedly responds to DTMF signals from an end-point terminal to create a conference. Such systems however, impose DTMF codes on the video or audio network that sustains the conference and apparently do not contemplate incompatibilities between participant end-point equipment.
What is needed therefore, is an economical video conferencing switching system that may be controlled by a participant through a control network separate from the network which sustains the conference and which displays attendant compatibility for disparate participant terminal equipment while providing a straight-forward control system and methodology.